1. Field of the Invention
The invention relates to material transport systems and, more particularly, is directed towards an injector for injecting particulate solids into a pressurized transport line.
2. Description of the Prior Art
Mining of coal in modern underground mines involves a highly mechanized operation. Most coal is cut by large continuous mining machines which have large rotating cutting drums. In one haulage system, the cut coal is carried away from the mine face on a short conveyor and fed into a shuttle car. Due to space limitations in the mine, only one shuttle car can be accomodated in the loading area at one time. This batch nature of the shuttle car configuration limits the duty cycle of the continuous mining machine and reduces the productivity of the mining operation. In another haulage system, the cut coal is fed continuously rather than in batches. This system top sizes the coal, premixes it with water in a hopper and pumps the mixture with a centrifugal slurry pump to a preparation plant outside of the mine. Slurry pumps are too large to be used in low coal seams. In addition, slurry mixing prior to injection is impractical in low coal seams because of the level control problem associated with shallow hoppers. Centrifugal pumps for transporting particulate solids suffer from the disadvantage that increasing pressure within the pump results in a decreasing flow rate. A need exists for an improved injector for injecting particulate solids into pressurized transport lines.